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2017 Grants - Su

Amyloid PET as a Biomarker for White Matter Integrity in Alzheimer's Disease

Yi Su, Ph.D.
Washington University in St. Louis
St. Louis, Missouri

2017 Alzheimer's Association Research Grant (AARG)

Could amyloid PET imaging be used to tell us more about possible damage occurring in the brain's white matter associated with Alzheimer's?

Background
In the last decade, researchers have developed methods for visualizing amyloid plaques in the brain using positron emission tomography (PET) brain imaging. The methods involve the use of a radioactive dye that binds to amyloid plaque, allowing the plaques to be visualized with PET imaging. These methods are now available for use in medical clinics under appropriate conditions.

Another type of brain imaging is used to visualize brain white matter. Brain white matter comprises of the long fibers through which nerve cells connect to each other; it is white because of the fatty material that forms the protective layers that surround those fibers. Changes in brain white matter are a common feature of Alzheimer's disease and other degenerative brain diseases.

Even though the dyes used in amyloid PET bind mostly to amyloid plaques, they also bind to white matter to a small degree. Such white matter binding could cause misinterpretation of amyloid PET images, but it could also be a sensitive and useful way to detect subtle changes in white matter integrity

Research Plan
Yi Su, Ph.D., and colleagues have proposed detailed studies of how amyloid dyes bind to brain white matter, how white matter integrity affects amyloid PET imaging, and how imaging of white matter integrity can reveal early evidence of disease in the brain; white matter integrity declines with the progression of Alzheimer's. The researchers plan to use data and images already available from a large study of brain imaging. Unlike the previous investigators, Dr. Su and colleagues will analyze how white matter integrity affected the amyloid PET images. The researchers will also compare amyloid PET images with data from autopsy studies to understand how amyloid dyes bind to brain white matter. Finally, Dr. Su's team will study how changes in amyloid PET images over time reveal changes in brain white matter.

Impact
These studies will help researchers and clinicians obtain more accurate and informative amyloid PET images in people suspected of having Alzheimer's disease. Furthermore, they may reveal new and more sensitive ways to detect early changes in brain structure that indicate the presence of disease in the living brain.